4800 plus maldi tof mass spectrometer

Chemical reagents and solvents were purchased from various commercial suppliers and used without further purification. Thin-layer chromatography (TLC) was carried out using Sorbfil aluminum sheets (Imid, Krasnodar, Russia) and visualized by UV absorption or stained with 2% H₂SO₄ in EtOH and heated. Column chromatography was performed using silica gel (particle size 0.06–0.2 mm, Sigma–Aldrich, Burlington, MA, USA). Nuclear magnetic resonance spectra were obtained with a Bruker AMX400 spectrometer. MALDI mass spectra were recorded with a 4800 Plus MALDI-TOF mass spectrometer (AB Sciex, Framingham, MA, USA). Research-grade human thrombin from plasma for clotting studies was purchased from Renam (Moscow, Russia). Fibrinogen from human plasma was obtained from Sigma–Aldrich. Standard reagents for automated oligonucleotide synthesis were purchased from Glen Research (Sterling, VA, USA).

The mass spectra of TBA conjugates were acquired using an Ultraflex MALDI-TOF/TOF mass spectrometer (Bruker Daltonics, Billerica, USA) and a 4800 Plus MALDI-TOF mass spectrometer (AB Sciex, Framingham, MA, USA) in the linear mode. The analysis was performed using 0.25 M aqueous 3-hydroxypicolinic acid as the matrix and 10 mM diammonium citrate as an additive. Spectra were recorded for positive ions. Before analysis, the samples were treated with Dowex 50WX8 in ammonium form.